Method or apparatus for producing pictures in colors



B. D. UNDERHILL.

METHOD OR APPARATUS FOR PRODUCING PICTURES IN COLORS.

APPLICATION'HLED NOV; 24, I916.

Patented May 25, 1920.

2 SHEETS-SHEET 1.

811 00 nrot' 61 Oli cp B. D. UNDERHILL.

METHOD 0R APPARATUS FOR PRODUCING PICTURES IN COLORS.

APPLICA iON FILED N0\I.24.1916.

Patented May 25, 19209 2 SHEETSSHEET 2.

Suva wrot- FUNITFEDTSITATEXZS PA BENJAMIN D. UNDERHILL, on NEW CANAAN, CONNECTICUT,

PLUMB, OF NEWARK, 1\TEW JERSEY.,

TENT OFFICE.

METHOD 0R APPARATUS FOR PRODUCING PICTURES IN COLORS. I

' Application filed November 24, 1916. Serial No. 133,120.

To all/whom it may concern: 4

Be it known that I, BENJAMIN. D. UNDER- HILL, a citizen of the United States, and a resident of New Canaan, county of F airfield,

State of Connecticut, haveinvented certain new and useful Improvements in'Methods or Apparatus for Producing Pictures in Color; and I do hereby declare the following to be a full, clear, and exact description paratus for taking photographs for pro jection and for projecting such pictures in their natural colors, and has for its object to provide a method for producing pictures of this character which may be carried out without the use of specially ground or reconstructed lenses or other expensive apparatus.

My invention is particularly applicable to the production ofpictures in colors in which the colors are formed of two components only, although the invention is applicable to the useof three colors also.

v A furt'her'object of'the invention is to provide an apparatuswhich may be used both i for taking and projecting the pictures with a simple change in'the adjustment of the parts to adapt the apparatus for one purpose or the other.

A further object of the invention is to provide an apparatus of the character described by means of which identical views may be simultaneously taken from points so little separated as not to produce a distin uishable difference in the pictures, whereby a perfect matching of the different colored components of the picture may be secured.

With the above objects in view, my invention consists of the method and appa ratus hereinafter described, taken in connectibn with the accompanying ,drawlngs wherein I have illustrated a preferred form of optical system for carrying my method into effect. i

In sa'id drawings:- W

Figure -1 is a horizontal sectional view through an optical tube containing the elements arranged for taking pictures to be r ai Fig. 2 is a similar view of the tube with it appertains to Referring to the drawings,

tion;

Fig. 3'is an end elevation of the tube shownin Fig. 1 looking fromthe'right;

Fig. 4 is the optical elements arranged for projeca sectional view on line 4 -4 of- 1- v Specification of Letters Patent. Patentedluay.35 1920,

Fi 1; l

ig. 5 is a sectional View on line 5--5 of Fig.1; i

Fig. 6 is a sectional view on line 6-6 of F ismodified arrangement of only for taking the pictures;

Fig. 7 is a horizontal sectional View of lenses adapted Fig. 8 is a similar view of a modified structure for projecting the pictures;

F igs.- {land 10 are transverse sections on the correspondingly numbered lines of Figs. 7 and 8, respectively;

-Fig.- 11 is across sectional view ofa modified lens structure in which the lenses are cut to utilize the entire area of" the diaphragm opening; and F ig. 12 is a similar view showing a similar modification in Which'three lenses are employed instead of 2. I

particularly Figs. 1. to 6, 1 indicates a metal tube of ordinary character employed for lens mounts. Mounted in the tube 1 are two smaller tubes 2 and 3, the two smaller tubes fitting. closely within the larger tube, the contacting. faces of. the two smaller tubes being preferably ground away to reduce the'thickness of the metal between the two tubes as much as possible. Each of thesmall tubes is equipped with suitable lenses 4 at each end, the lenses .of the two tubcs'being identical or of very slightly different focal lengths for the purpose hereinafter described. The lenses are ordinary'photographic lenses and may be of any desired character, according to the speed and definition required in the pictures,

each tube considered alone being an ordinary photographic lens system. The larger tube 1' is provided at each end.

, with a stop preferably an iris diaphragm 5,

working as closely as possible against the ends of the small tubes. The small tubes 2 and 3 are each in two sections as shown, the two sections being separated by a third stop or iris diaphragm 7. Between the diaphragm 7 and the adjacentends of the rear tube sections thereis arranged a disk 8 of a diameter somewhat greater than twice the diameter of the tube 1, the disk being mounted for rotary-adjustment on a pivot 9 set in a reinforcing collar 10 surrounding the tube 1, and providing a support 'for the diaphragm 7. Set in the disk 8 at spaced the lens system are provided without moving the lens tube with relation to the film or plate. The lenses 11 are each somewhat larger than the lenses of the small tubes and are so positioned in disk 8 that the center of the lens 11 in operative position will coincide with the line of contact of the two small tubes 2 and 3. In addition to the four lenses set in the disk 8 there is provided an opening or blank 12 large enough to allow substantially the full diameter of the lens tubes to be unobstructed, as shown in Fig. 2, in which figure the disk 8 is shown adjusted for projection.

The large tubel is provided at each end i with slide carriers 13 and 14, respectively,

here shown as fixed to the outer cover of the iris diaphragms 5. The slide carriers are preferably stamped out of sheet metal and are of the usual rectangular shape open at one side. The purpose of the slide carriers is to provide support for prismatic lenses 15 mounted as shown in detail in Fig. 6 for rotation in a square frame 16 fitting in the slide carrier by which the centers of the prismatic lenses will be maintained in line with the centers of the small tubes. Each prismatic lens issuppo'rted in a half ring 17 having gear teeth formed on its outer periphery and positioned to mesh with a rack 18slid'ingly mounted in the frame 16.

When the lens system is used on a camera the prismatic lenses are placed in the slide carrier at'the end toward the film to deflect the light rays through the two lens systems away from each other so that the centers of the exposed areas forming the two pictures will be separated to a greater extent than the centers of the uncovered portions of the lenses. In projecting the pictures the prisms are placed in their slide carrier at the outer end of the lens tube to provide a convenient means for superimposing the pictures on the screen in exact registration with each other.

Attached to the flange of the rear slide carrier 14 is a tubular extension 20 of the full diameter-of the tube 1; by'means of which the lenses may be detachably mounted for telescopic adjustment in the fixed tube sections 21 with which the camera and the projection machine will be provided.

The slide carrier llat the outer end of the tube 1 is shaped to receive and support the frame of a light filter 22 comprising a pair of glass plates supporting between them two differently colored pieces of gelatin such as commonly employed for light filtersin color photography work. It will of course be understood that one color of gelatin completely covers one of the small tubes and the other piece completely covers-the other tube, and that the colors selected will be the so-called 2 color opposites which have heretofore been employed for like purpose.

In Fig. 1 I have shown the optical elements arranged for taking pictures. For this purpose the several diaphragms 5 and 7 are adjusted so that the diaphragm openings are no greater than the distance between the centers of the two small tubes whereby only a portion of, the adjacent halves of the lenses at the ends of the small tubes are uncovered, as more clearly shown in Fig. 3. The frame 16 carrying the prismatic lenses is placed in the slide carrier 14. at the rear end of the large tube 1, and the color filter is supported on the slide carrier at the opposite end of the large tube 1. The

color filter may be arranged at the other end of the lens tube if desired, or in front of the film in the camera.

justable diaphragms, the pictures are taken from points so little separated as to produce substantially identical images through the two lens systems. Without the prisms at the ends of the small lens tubes the individual pictures on the screen are limited in size to the distance between the centers of the lenses or to substantially the same area as the diaphragm openings, but with the prisms the rays of light through the different lenses may be diverged to any extent desired by rotating the prisms to bring their thinnest portions more or less to the'plane of the optical axes of the two lenssystems.

When thepicture is projected the elements of the optical system are arranged in the manner shown in Fig. 2. The prismatic lenses are placed in the slide carrier 13 at the front end of the optical tube immediately behind the color filter. The various diaphragms are open. to their full extent and the disk 8 is adjusted to bring the opening 12 into position for the two small tubes to be unobstructed for the full diameter of the lenses. The positive film printed from the screen, the two pictures probably mismatchpictures being simultaneously projected through the two lens systems. During the projection of the picture the lens may be focused by adjusting the tube *1 in and out in the tube section 21. The" lens system of each small tube projects-the picture on the corresponding side of the. film to the screen to occupy substantially the full area of the ing prisms.

As the pictures are taken from points having slightly if projected without the correct- 'ing but little separation due to the small area of the diaphragm opening, the two pictures will be substantially identical instead of presenting the differences of .a stereoscopic pair taken with lenses separated to to give a sharp picture of excellent definition and without the'differently colored border heretofore unavoidable when two simultaneously taken pictures are projected on the screen.

f In taking the pictures the small exposed portion of each lens has the same effect as a large lens wlien the diaphragms areopen. That is, the picture produced is the same as far as focus, etc., is concerned, but the appearance of the two pictures considered with relation to the point from which takenis the same as if the lenses had their geometrical centers at the center of the exposed portion of the lens, so that .by this arrangement I am able to use lenses offair size which can be accurately ground and matched, and at the same time secure all the advantages of closely positioned lenses of very minute diameter. I

I have shown the prismatic lenses, the

focusing lens carrier and the diaphragm as arranged for adjustment in order that the same lenses may be used'for taking and projection. In commercial use separate systems will more conveniently be employed for the cameraand the projector,and each system may have its prisms permanently fixed in place or the prisms may be dispensed with..

This adjustment or some other mechanism forthesame purpose is, however, preferable in projection for securing accurate matching of the pictures.

1 In Fig. '7 I have illustrated an arrangement of lenses, etc., adapted solely for taking pictures in accordance with my improved method, whereby the structure is much simplified. As here shown, the two lens systems are supported in an outer casing 50, which may be of elliptical cross section as shown in Fig. 9, the two lens tubes be-- ing fixetlin place with their adjacent edges in close contact. Preferably the metal of the tube is cut away or left very thin on the adjacent sides of the lens tubes so that the optical'centersof'thelenses ma be brought as close together as possible. Iii the drawings I have. shown the lens tubes as complete throughout their .circumference, but they may be cut away as described, or part of the glass of each lens may be sawed off on adjacent sides as shown more particularly in Fig. ll'so that the entire area of the opening in the diaphragm 51 is backed by a portion of the lenses.

Theedge of the opening in the diaphragm- 51 should coincide substantially with the optical centers of the lenses, and the diaphragms may each be formed of a single piece of sheet metal with'a fixed opening instead of the iris diaphragm of the previously described construction.

Each lens tube is divided in two sections to provide for an interposed disk 52 mounted for-rotation on a pin 53 supported by a bracket 5(1 attached to one of the curved side. edgesof the elliptical casing 50. The disk 52 carries a series of focusing lenses 55 as shown in Fig. 9 whereby the lens system may be supported in fixed relation to the plane of the plate or film upon which the photograph is to be taken.

- The rear endsof the front sections of the lens tubes are closed by a middle diaphragm plate 56 having a central aperture equal in size to the aperture of the diaphragm 51 and mounted in each rear section of the lens tubes is asheet'metal Web or shield 57, each of which is .cut 'away on its inner side to expose a portion of the rear lens corresponding in shape and area with the exposed portion of the front lenses. ported in the casing back of the. lens tubes are a pair of prisms or prismatic lenses 58 with their inner edges adjacent, to produce a divergence of the images formed by the two separate lens systems, and back of the prismatic lenses and also fixed in the casing 50. is a frame 59 supporting the color filters of substantially complementary colors, whereby the exposures made through one lens system will have a different color value from theexposures effected through the other. lens system.

A separate web or division-plate as shown in Figs. 1 and 2 will of course extend from the color filters into the camera in close Fixedly supproximity to the film, so, that each side of the film will be exposed only to the light rays through thelens system and color filter along that side. 7 i

It will of coursebe understood that a camera equipped with my improved lens system will be supplied with the usual shut ter, film feed andother accessories necessary for the proper exposure or manipula tion of the plate or film as the case may be. With the lens system arranged only for the taking of pictures, all the adjustable parts except the focusing disk 52 are dispensed with in order to thereby much simplify the apparatus and reduce its cost of manufacture and liability to derangement in the hands of inexperienced operators. The focusing disk will contain five or more lenses of different focus whereby upon determining the approximate distance of the principal object in the field to be photographed the lens disk will be adjusted to bring the proper lens into action. Also, the prisms 58 may be dispensed with if desired, but their use is advantageous in that with the other elements of the system the same, larger pictures may be taken as explained above.

Pictures taken with the above described lens system may be projected with a projecting apparatus equipped with the lens arrangement of Fig. 2, but I refer to provide a simpler arrangement of the lenses when the projector is not adapted for use alternately as a camera. A lens system of this character as illustrated in Fig. 8

comprises outer elliptical casing 60 in which are supported for lateral movement toward and away from each other two lens tubes 61, each of which is equipped withtwo or more lenses forming a' complete lens system for projection. The lens tubes 61 are adjusted and maintained in adjusted position by means of a screw 62 having oppositely threaded portions working in correspondingly threaded ears 63 projecting respectively from the two lens tubes through suitable slots 64 in the upper side of the elliptical casing 60. The screw 62 is mounted for rotation in a fixed projection 65 on the casing 60 between the pins 63, the screw being held against longitudinal movement by a pin and groove bearing, 65. By rotating the screw in either' direction by means of the knurled thumb piece at tached to one end, the lenses will be shifted toward and'away from each other while maintaining their centers equidistant from the center of the elliptical casing.

I have shown the casing 60 as also 'equipped with prisms 66 at its outer end,

the prisms being arranged with their thin edges adjacent to effect a lateral deflection of the light rays to assist in superimposing the two pictures on the screen. "These prisms may, however, be dispensed with and the entire matching of thepictures effected by "the lateral adjustment of the two lens tubes toward and away from each other. If, prisms are used a smaller lateral adjustment of the two lens tubes will be necessary to effect a proper registration of the pictures. The color filter'67 will be mounted in the usual manner on the front end of the casing 60, to give the proper 'cused by altering its. position instead of by interposing lenses of different values in the system. For this purpose the tube 60 is supported in a casing 68 fixed to the front wall69 of the projecting machine, the two parts being connected by a suitable rack and pinion 70 whereby the tube may bereadily adjusted into and out of the casing 68.

I have shown and described the lenses employed in carrying out my invention as circular and with thin 'tubes on their adjacent sides to allow their being placed close together. I may, however, with advantage cut away a portion of the glass also on the adjacent edges of the lenses as shown in Fig. 11, so that the portion of the lens exposed by the opening in the diaphragm will be semi-circular instead of generally elliptical as where the circular lenses are used.

As shown in Fig. 11, the lens tube 61 and the lenses 61 are cut away on their meeting faces sufficiently to provide fiat surfaces equal in length to the diameter of the diaphragm opening, whereby the exposed area of the lens will be semi-circular as described. In each case the edge of the diaphragm opening will intersect the optical centers of the lenses so that with the diaphragm opening of the same size the images formed will be substantially the same whether the lenses are cut away on their adjacent edges or not, but when they are cut away, the lenses will have an effective area of greater size and consequently will transmit more light or be more rapid in their action.

I have shown and described my improved method as adapted for a two-color system of color photography,but the invention may be adapted for'a three-color system, such, for example, as described in the patent to Holbrook, No. 1,151,786, of August 31, 1915.

In Fig. 12 I have indicated diagrammatically a suitable arrangement of lenses for the purpose. As here shown, the outer casing 70 is circular and contains three small lens'tubes which may be arranged with the two upper ones parallel and horizontal, and the lower one with its center equidistant from the centers of the two upper lenses. A diaphragm 72 having a central circular opening covers one end of the casing 70, the edges of the diaphragm opening preferably registering with the optical centers of the lenses.

The various lenses may be uncut, that is, circular in shape, as in the construction illustrated in Figs. 1 and 2, but I prefer to cut away the meeting edges of the three lenses and their tubes as shown'in Fig. 12 so that the edges of three lenses meet in the center of the diaphragm opening.

In other respects the three-color system will be similar to the two-color system previously described. The focus may be secured by a focusing disk having lenses of different values somewhat larger than the diaphragm opening and the lens tubes may or may not be provided with prisms. \Vhen prisms are used the prisms of the lower lens will be arranged to deflect the rays downward to increase the area of the field. Of course, when three color filters are used the colors will be the shades for the well known three-color systems.

One advantage that may be mentioned in providing separate lenses for the three-color system instead of a single lens made of the reversed sectors, as in the Holbrook patent is that the lenses of the three separate tubes may be of slightly different values to compensate for the different lengths of the light rays of the different component colors, the

longer red rays through the red filter requiring a slightly longer focal length of lens to secure an exact focus than the rays of shorter Wave length through the other filters.

Further, in using separate lenses, each lens may be'mounted in a separate tube and the three tubes fitted in the outer casing, the

smaller tubesbeing cut away through such a small portion of their complete circumference as to form rigid supports for the lenses when merely assembled and clamped in the outer casing. WVhen the lens is made up from reversed sectors, the parts have to be very carefully matched and mounted as a single lens, the operation being both expensive and difficult.

I claim:

1. The method of producing projected colored pictures which consists in photographing the view to be projected through two separate optical systems having color screens of different colors and with their optical axes parallel and closely adjacent and with only adjacent portions of said lenses exposed to the light rays, deflecting the light rays forming each view away from each other to increase the distance between the centers of the pictures and then projecting the pictures so produced through corresponding color screens and in superimposed relation through lens systems having a greater separation between the centers of their exposed areas than between the centers of the exposed areas of the taking lenses.

2. An apparatus for taking pictures for color projection or projecting such pictures comprising a pair of substantially identical lens systems mounted closely adjacent and in parallel relation, each lens system having only the portion to the side of its optical system adjacent the other lens system effective, and differently colored light filters in each system, said systems including a series of lenses of different power to be interchangeably interposed in the systems to vary the focus of the systems as a whole.

In testimony whereof I afiix my signature.

BENJAMIN D. UN DERHILL, 

